Emergency machine off feature with safety control interface

ABSTRACT

An apparatus for implementing an emergency machine off circuit of a fabrication system, includes: at least one safety switch adapted for shunting an operation enable signal from a piece of equipment selected for removal from service, the switch also removing from service supplemental devices for the selected equipment. A semiconductor fabrication system and a method for removing equipment from service are provided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates generally to electrical circuits forsystem safety controls and, in particular, to emergency machine offsystem disabling circuits.

2. Description of the Related Art

A variety of equipment systems are utilized within the semiconductorfabrication industry, which include peripherals and ancillarycomponents. From time to time, equipment systems require power down tofacilitate safe service. A complicating factor arises when componentsand/or sub assemblies fail and/or require emergency service; thereby,impacting the entire system.

Industry safety standards require the use of an “emergency off circuit”(EMO) during any unplanned shutdowns and/or repairs activities.Activation of the EMO causes the entire system to halt/shutdown/poweroff. Therefore, some service personnel may attempt to override the EMOsafety circuit to facilitate continued equipment operation duringservice procedures, fostering creating an unsafe condition. Variousunsafe techniques are used. For example, service personnel can “jumperout” the systems EMO circuit rendering it inoperative, increasing therisk of employee injury during the service activity. Unfortunately, thistechnique does not control or protect personnel from all remaininghazardous energy sources within the system. Continuing operation in thismanner may lead to significant personal injury, when for example, whentoxic gas is delivered to a component that is not operational orinvolved with the primary maintenance activity.

What is needed are apparatus providing a safety control circuit design,such as the controls provided herein. When implemented, the apparatusprovide safe controls for de-energizing/isolating selected equipmentsystem components and sub-components, while other parts of the systemremain active while ensuring all safety controls circuits remain fullyfunctional for all aspects of the equipment system still in use.

BRIEF SUMMARY OF THE INVENTION

In an embodiment, an apparatus for implementing an emergency machine off(EMO) circuit of a fabrication system, is provided and includes: atleast one safety switch adapted for shunting an operation enable signalfrom a piece of equipment selected for removal from service, the switchalso removing from service supplemental devices for the selectedequipment.

In another embodiment, a semiconductor fabrication system is providedand includes: an emergency machine off (EMO) circuit including an EMOloop for providing an operation enable to a plurality of pieces ofequipment of the fabrication system, the loop including at least onesafety switch adapted for shunting an operation enable signal from apiece of equipment selected for removal from service, the switch alsoremoving from service supplemental devices for the selected equipment.

In a further embodiment, a method for removing equipment in afabrication system from service, is provided and includes: selectingequipment for removal from service; shunting an operation enable signalfrom the selected equipment and removing supplemental devices associatedwith the selected equipment from service.

Other systems, methods, and/or computer program products according toembodiments will be or become apparent to one with skill in the art uponreview of the following drawings and detailed description. It isintended that all such additional systems, methods, and/or computerprogram products be included within this description, be within thescope of the present invention, and be protected by the accompanyingclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other objects, features, andadvantages of the invention are apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 depicts aspects of a prior art “emergency machine off” circuitfor a fabrication system;

FIG. 2 depicts an exemplary safety switch;

FIG. 3 depicts a side view of the safety switch of FIG. 2;

FIG. 4 depicts a multiple safety switch in an operational condition;

FIG. 5 depicts a functional diagram for the switch arrangement of FIG.4;

FIG. 6 depicts the multiple safety switch of FIG. 4, with one piece ofequipment removed from service; and

FIG. 7 depicts a functional diagram for the switch arrangement of FIG.6.

The detailed description explains the preferred embodiments of theinvention, together with advantages and features, by way of example withreference to the drawings.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed are techniques for providing improved safety controls to afabrication system. The controls may be used in conjunction withexisting controls, such as an “Emergency Machine Off” (EMO) system. Thecontrols may be used advantageously with other existing control systems,and are not limited to use in semiconductor fabrication systems.

As disclosed herein, the safety controls are discussed with relation toan embodiment of a semiconductor fabrication system. It is recognizedthat many embodiments of fabrication systems are known and may make useof the teachings herein. Further, other systems, such as powergeneration, flow controls, process controls, large scale manufacturingand other such systems may make use of the teachings herein.Accordingly, the ensuing discussion regarding semiconductor fabricationis not limiting of the invention and is merely illustrative.

First, some definitions and useful terms are provided. The term“equipment” generally makes reference to a part of a fabrication system.Most often, as discussed herein, the term “equipment” refers to aportion of the fabrication system (e.g., one or more components) that isnot operating as desired, and therefore initiates or is cause toinitiate, actuation of an “emergency machine off” function. The term“supplemental device” makes reference to devices associated with or insupport of selected equipment.

In an exemplary embodiment, the “fabrication system” is a chemical vapordeposition (CVD) system. Many embodiments of CVD systems are known.These include, without limitation, systems classified by operatingpressure, such as: atmospheric pressure CVD (APCVD); low-pressure CVD(LPCVD); ultrahigh vacuum CVD (UHVCVD). Other systems include: aerosolassisted CVD (AACVD); direct liquid injection CVD (DLICVD); plasmamethods (PCVD); microwave plasma-assisted CVD (MPCVD); plasma-enhancedCVD (PECVD); remote plasma-enhanced CVD (RPECVD); atomic layer CVD(ALCVD); hot wire CVD (HWCVD) (also known as “catalytic CVD” (Cat-CVD)or “hot filament CVD” (HFCVD); metalorganic chemical vapor deposition(MOCVD); rapid thermal CVD (RTCVD); vapor phase epitaxy (VPE) andothers. Aside from CVD, the fabrication system may include systemsimplementing processes for any one of deposition, removal, patterning,and modification of electrical properties, as well as other processesand techniques. As used herein, “Emergency Machine Off” (EMO) circuitmakes reference to a circuit that provides for shutdown of thefabrication system. The EMO is generally a control circuit that, whendeactivated, places the fabrication system into a complete shutdown. An“EMO Loop” generally includes a loop providing at least one of a powersignal and a set of machine executable instructions (i.e., some form ofan operation enable signal) to pieces of equipment coupled to the EMOcircuit.

As used herein, the term “circuit” generally makes reference tohardwired circuits, in particular this is the case with the prior art.However, it is recognized that aspects of control systems may beimplemented in software. Accordingly, circuits implementing the controlsystems related to the teachings herein may be implemented in softwareor hardware and in various combinations as appropriate. Thus, thedrawings provided herein may be considered descriptive of logic as wellas actual wiring and/or other components. In that regard, the operationenable signal generally provides at least one of a power signal and aset of machine executable instructions. Such instructions may beinterpreted by processing and other features of equipment coupled to thecircuit.

As discussed above, in the prior art, all components of a fabricationsystem are typically powered off when equipment within the EMO loop mustbe replaced or serviced. Referring now to FIG. 1, there are shownaspects of a current design for an EMO function.

In FIG. 1, a prior art Emergency Machine Off (EMO) circuit 1 includes anelectrical box 2, a control device 4, a plurality of supplementaldevices 6 (shown here as supplies of toxic gas that correlate to certainsystem equipment), a plurality of equipment 8 which are generally partof the fabrication system 10, a heat exchanger 7 and a chiller 9 (bothof which are included in the fabrication system 10). As depicted in FIG.1, certain aspects are linked by at least one EMO wire, depicted bysingle dotted lines. Other aspects are linked by at least one controldevice wire, depicted by single dashed lines.

As shown in FIG. 1, the plurality of equipment 8 may include variouscomponents, including, for example, a pump, a power supply, a pressuresupply, a vacuum supply, a spray system, a vaporizing system, adeposition system, a plasma generator, a lamp, a laser, a lithographysystem and the like. Accordingly, the plurality of supplemental devices6 include devices such as supplies of materials (including liquid,vapor, and other forms), delivery systems for the supplies, powersupplies and other such items as used in a fabrication system 10. Asdepicted in FIG. 1, certain ones of the supplemental devices 6 maycorrelate with certain ones of the equipment 8.

It should be recognized that the EMO typically places the equipment intoa safe shutdown condition and will restrict all hazardous potentials toa main power enclosure, such as the electrical box 2. Accordingly, allhazardous voltage is removed from the equipment 8, flow of hazardousproduction materials is stopped, radiation sources are de-energized orcontained, capacitors are grounded, all moving parts are stopped,internal and external heat sources are shut off, and the fabricationsystem 10 as a whole presents minimum hazard to personnel or thefacility. Accordingly, and for example, a fault with equipment A willinitiate shutdown of the entire fabrication system 10. Accordingly, animproved EMO 1 that includes a safety control interface for removingportions of the fabrication system 10 from service is provided herein.

Now with reference to FIG. 2, aspects of an embodiment of a safetyswitch 20 are depicted. The safety switch 20 includes a design forproviding a momentary lockout for shunt and process control. The designis equipped with double-pole, double-throw switching. In this example,an area monitor process shutdown 22 is included. The safety switch 20includes an EMO shunt 21 for shunting process signals. In anotheraspect, FIG. 3 depicts a side view of the safety switch 20.

In the embodiment depicted in FIG. 3, the safety switch 20 includes alockout port 31. The lockout port 31 provides for manual lockout of anassociated equipment 8. The lockout may be lifted manually by personnelwhen restoration to service of the respective equipment 8 is desired.

One skilled in the art will recognize that the double-pole, double-throwswitching design is merely one embodiment of a safety switch 20, andthat other embodiments may be used. For example, other designs of EMOcircuits 1 may make use of switches including at least one of asingle-pole, single-throw; a single-pole, double-throw; a single-polechangeover; a single-pole, centre off, a double-pole, single-throw; adouble-pole changeover; and a double-pole, centre off switch as thesafety switch 20 (as well as other switch designs).

In FIG. 4, aspects of a multiple safety switch 40 are provided. In thisexemplary embodiment, operation of a control device 3 and associatedsupply of toxic gas is controlled by a plurality of the safety switches20. Each control device 3 is associated with a respective piece ofequipment 8. As depicted in FIG. 4, each of the pieces of equipment 8(i.e., equipment A, B and C) are operational, and the associated controldevices 3 permit delivery of toxic gas (i.e., are in an “ON” state).This may be better understood with reference to FIG. 5.

In FIG. 5, an EMO switching box 50 is shown. In this embodiment, the EMOswitching box 50 includes a plurality of safety switches 20. Some of thesafety switches 20 may be included within the multiple safety switch 40.For example, single safety switches 20 may be associated with the heatexchanger 7 and the chiller 9, while the equipment 8 (A, B and C) arecontrolled by the multiple safety switch 40. Various components may becoupled to the safety switches 20, 40 (as indicated by the single dottedlines), and may be coupled to the control device 3 as indicated by thesingle dashed lines.

Now with reference to FIG. 6, aspects of operation of the multiplesafety switch 40 are depicted. In FIG. 6, a first safety switch 20(associated with equipment A) is depressed. This provides for removingequipment A from service. That is, one skilled in the art will recognizethat the safety switch 20 provides a shunt on the EMO circuit,effectively disengaging equipment A (shown as detached from the EMO 1circuit). As shown in FIG. 6, a lock 60 may be placed for locking therespective safety switch 20. In some embodiments, the lock 60 makes useof the lockout port 31 for providing the locking. A functional diagramfor this embodiment is depicted in FIG. 7.

Various benefits are realized by use of EMO safety switches 20, 40. Forexample, unsafe workaround devices, such as a jumper, are no longerneeded. When a piece of equipment is removed from service, the EMO loopcontinues to work on the rest of the equipment All tool hazards can beselectively and safely turned off, while maintaining functionality ofthe EMO 1 loop circuit. Thus, the safety switch 20, 40 provides a failsafe lockable momentary switch. Only after the lock 60 is removed cantool hazards be restored to operation.

Accordingly, an improved EMO circuit 1 is provided. The EMO circuit 1disclosed herein includes at least one safety switch 20. The safetyswitch 20 may be used shunt the operation enable signal to removeselected equipment 8 from service, without deactivation of the EMO loop.The removal from service may include shutting down hazards and othersupplemental devices associated with the selected equipment.

Accordingly, in one embodiment, a fabrication system 10 includes the EMOcircuit 1 including at least one safety switch 20, 40. The fabricationsystem 10 that includes the EMO circuit 1 is generally enabled forcontinued operation on segments that are not removed from service. Ofcourse, one skilled in the art will recognize that this is simplified insome respects. For example, a user may wish to terminate upstreamproduction when downstream repairs are underway, thus avoiding abacklog. Accordingly, advanced switching and other designs may beincorporated.

As described above, embodiments can be embodied in the form ofcomputer-implemented processes and apparatuses for practicing thoseprocesses. In some exemplary embodiments, the invention is embodied incomputer program code executed by one or more network elements.Embodiments include computer program code containing instructionsembodied in tangible media, such as floppy diskettes, CD-ROMs, harddrives, or any other computer-readable storage medium, wherein, when thecomputer program code is loaded into and executed by a computer, thecomputer becomes an apparatus for practicing the invention. Embodimentsinclude computer program code, for example, whether stored in a storagemedium, loaded into and/or executed by a computer, or transmitted oversome transmission medium, such as over electrical wiring or cabling,through fiber optics, or via electromagnetic radiation, wherein, whenthe computer program code is loaded into and executed by a computer, thecomputer becomes an apparatus for practicing the invention. Whenimplemented on a general-purpose microprocessor, the computer programcode segments configure the microprocessor to create specific logiccircuits.

In some embodiments, the safety interface is implemented in software(i.e., machine executable instructions stored on machine readablemedia). The implementation may include a display that provides conditionon each of the safety switches 20, 40 and may include operator controlsfor activation of selected safety switches 20, 40. Software equivalentsto the foregoing hardware may be included. For example, the lockout port31, the various switch designs (i.e., logic) may be implemented insoftware.

While the invention has been described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims. Moreover, the use of the terms first, second, etc. do not denoteany order or importance, but rather the terms first, second, etc. areused to distinguish one element from another. Furthermore, the use ofthe terms a, an, etc. do not denote a limitation of quantity, but ratherdenote the presence of at least one of the referenced item.

1. An apparatus for implementing an emergency machine off (EMO) circuitof a semiconductor fabrication system, the apparatus comprising: a firstsafety switch comprising at least one of a double-dipole, double-throwswitch, a single-pole, single-throw switch; a single-pole, double-throwswitch; a single-pole changeover switch; a single-pole, centre offswitch; a double-pole, single-throw switch; a double-pole changeoverswitch; and a double-pole, centre off switch, the first safety switchcomprising a lock out port and adapted for shunting an operation enablesignal comprising at least one of a power signal and a set of machineexecutable instructions from first equipment selected for removal fromservice, the first safety switch also interfacing with a control deviceassociated with a first supplemental device such that when the firstsafety switch shunts the operation enable signal to the first equipment,the control device removes from service the first supplemental device; asecond safety switch comprising at least one of a double-dipole,double-throw switch, a single-pole, single-throw switch; a single-pole,double-throw switch; a single-pole changeover switch; a single-pole,centre off switch; a double-pole, single-throw switch; a double-polechangeover switch; and a double-pole, centre off switch, the secondsafety switch comprising a lock out port and adapted for shunting anoperation enable signal comprising at least one of a power signal and aset of machine executable instructions from second equipment selectedfor removal from service, the second safety switch also interfacing witha control device associated with a second supplemental device such thatwhen the second safety switch shunts the operation enable signal to thesecond equipment, the control device removes from service the secondsupplemental device, the second safety switch operating independently ofthe first safety switch; wherein the semiconductor fabrication systemcomprises at least one of an atmospheric pressure chemical vapordeposition system; a low-pressure chemical vapor deposition system; aultrahigh vacuum chemical vapor deposition system; an aerosol assistedchemical vapor deposition system; a direct liquid injection chemicalvapor deposition system; a plasma method chemical vapor depositionsystem; a microwave plasma-assisted chemical vapor deposition system; aplasma-enhanced chemical vapor deposition system; a remoteplasma-enhanced chemical vapor deposition system; an atomic layerchemical vapor deposition system; a hot wire chemical vapor depositionsystem; a metalorganic chemical vapor deposition system; a rapid thermalchemical vapor deposition system; a vapor phase epitaxy system; a systemimplementing a process for any one of deposition, removal, patterning,and modification of electrical properties; wherein the first equipmentand second equipment comprises at least one of a pump, a power supply, apressure supply, a vacuum supply, a spray system, a vaporizing system, adeposition system, a plasma generator, a lamp, a laser, and alithography system; and machine executable instructions stored onmachine readable media further comprising instructions for displaying astatus of the first safety switch and second safety switch andcontrolling a status of the first safety switch and second safetyswitch.